Info Catalog eintr: car & cdr eintr: car cdr & cons eintr: nthcdr

eintr: cons

 
 7.2 ‘cons’
 ==========
 
 The ‘cons’ function constructs lists; it is the inverse of ‘car’ and
 ‘cdr’.  For example, ‘cons’ can be used to make a four element list from
 the three element list, ‘(fir oak maple)’:
 
      (cons 'pine '(fir oak maple))
 
 After evaluating this list, you will see
 
      (pine fir oak maple)
 
 appear in the echo area.  ‘cons’ causes the creation of a new list in
 which the element is followed by the elements of the original list.
 
    We often say that ‘cons’ puts a new element at the beginning of a
 list, or that it attaches or pushes elements onto the list, but this
 phrasing can be misleading, since ‘cons’ does not change an existing
 list, but creates a new one.
 
    Like ‘car’ and ‘cdr’, ‘cons’ is non-destructive.
 

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· length                      How to find the length of a list.
 

Info Catalog eintr: car & cdr eintr: car cdr & cons eintr: nthcdr